The d.c. properties of an alkali plasma diode

Fang, Michael; Fraser, Duncan A. X.; Allen, J. E.

doi:10.1088/0022-3727/2/2/312

Cited by 22 publications

(11 citation statements)

References 10 publications

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“…The simultaneous excitation of high and low frequency modes in a plasma diode was also reported by Cutler & Burger (1966). Fang (1968) finds the oscillation frequency to be one third of the electron plasma frequency whereas Iannuzzi et al (1968) observed oscillations a t a frequency comparable with the plasma frequency.…”

Section: Introductionmentioning

confidence: 54%

“…The high frequency mode and the 'constant frequency' mode are usually observed over a similar range of applied potentials, although there are exceptions to this, as discussed later. Iannuzzi, Levine & Piperno (1968) and Fang et al (1969) and Fang (1968) have all reported observations of the high frequency mode of oscillation. The simultaneous excitation of high and low frequency modes in a plasma diode was also reported by Cutler & Burger (1966).…”

Section: Introductionmentioning

confidence: 94%

“…Before a perturbing potential difference C 541 ] is applied the plasma is current-free and is in therm al equilibrium. This particular plasma has been used previously by Fang, Fraser & Allen (1969), and Phelps & Allen (1976) for d.c. studies and by Allen, Fang & Fraser (1971) for low frequency oscillation studies. Three kinds of oscillation have so far been observed when a current above a critical level is passed through the plasma.…”

Section: Introductionmentioning

confidence: 99%

“…There are two low frequency modes 100 kHz) and a high frequency mode (ca. 300 MHz) the electron plasma frequency, / pe, w h e re /pe = (Fang 1968). The high frequency mode is the subject of the present investigation.!…”

Section: Introductionmentioning

confidence: 99%

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High frequency oscillations in a bounded thermally produced plasma

Phelps

Allen

1978

Proc. R. Soc. Lond. A

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Measurements are reported of a high frequency mode of oscillation of a current carrying, bounded, thermally produced plasma. The oscillation occurs at approximately a third of the electron plasma frequency. A linear theory is presented, which predicts an instability at this frequency. The electron and ion velocity distribution functions used in this theory are determined by the self-consistent d.c. potential distribution. An interesting feature is that the electron velocity distribution function is a discontinuous Maxwellian. The calculated frequency of the instability and its variation as a function of the plasma density agree very well with the experimental observations.

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Section: Introductionmentioning

confidence: 54%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High frequency oscillations in a bounded thermally produced plasma

Phelps

Allen

1978

Proc. R. Soc. Lond. A

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“…9 Then the vanishing current is simply expressed by n~ = rn*, while the global electroneutrality, equivalent to </>'( -d/2) = (j)'(d/2), can be given a precise analytical form thanks to the fact that the Poisson equation happens to take the form of a pseudopotential equation 10 …”

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confidence: 99%

Collisionless Heat Transport in a Stationary Bounded Plasma: Effect of Nonlocal Electroneutrality

Clause

Wallenborn

1984

Phys. Rev. Lett.

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Using a simple model of a plasma between two boundaries at which temperature is fixed, we investigate the thermal transport in the collisionless limit, relaxing the usual local neutrality assumption. For physically relevant external parameters, an analytical solution is found where the heat flux is reduced with respect to its value when local electroneutrality is assumed.PACS numbers: 52.25.Fi, 52.40.Kh The classical heat-transport problem in a weakly coupled plasma has recently received much attention in connection with the extension of the linear theory 1,2 into the nonlinear, large-temperaturegradient and thus less collisional regime. The interest for this problem is notably motivated by the physical conditions which occur in plasmas produced by high-power lasers. 3 Besides numerical works treating the Fokker-Planck equation, 4,5 analytical models have been developed to deal with an arbitrary collisionality parameter L/X where L is the macroscopic characteristic length and A the collisional mean free path. 6 " 8 When going from the collisional to the collisionless limit, the authors of the latter works essentially maintain or arrive at the assumption of strict local electroneutrality. This procedure is, however, questionable in the context of stationary states of bounded plasmas, as considered in their models. We aim here at evaluating the effect of relaxing local electroneutrality in the collisionless case, the plasma remaining globally neutral. More specifically, the modification introduced on the heat flux will be examined.We investigate a solution to the one-dimensional Vlasov-Poisson system, describing the electrons embedded in a uniform ion background of density n h charge number Z:(1) ldu where / is the electron distribution function, n(x) = Jd 3 vfis the electron number density, and 0 is the electric potential. The plasma is bounded by two thermostatic walls located at x = -d/2 and x = d/2, respectively, and at different temperatures T + and T~, respectively. We restrict our analysis to the case of a monotonic variation of , say cj)'(x) ^ 0 for instance, but the ratio r 2 = T + /T~ is allowed to take the value T h /T c as well as T c /T h , where T h and T c stand for the given hot and cold boundary temperatures, respectively. The microscopic boundary conditions are taken such that the distribution function for electrons flowing away from each wall is Maxwellian, with the wall temperature:Here, 0 ± = 0( +d/2), with 0 " = 0. The parameters n + , n ~, and + must be determined self-consistently according to three conditions: (i) a noncapture condition at the walls which implies that the electron current vanishes in the stationary state, (ii) global electroneutrality, and (iii) the electron density at the hot wall, n h , given, i.e., n ( -d/2) = n h in case r>\ while n(d/2) = n h in case r < 1. The formal solution of the Vlasov equation for the distribution function expressed in terms of the potential and satisfying the wall interaction conditions (2) can be constructed by proceeding as in Fang, ...

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